淅川地层小区寒武系层序划分

淅川地层小区寒武系划分为水沟口组、岳家坪组和蜈蚣丫组。底部与震旦系平行不整合接触,顶部与奥陶系整合或平行不整合接触,顶、底界面特征为Ⅱ型界面。地层层序分析以剖面研究为基础,在详细测制地层剖面的基础上划分出了46个基本层序,分析基本层序在纵横向上的变化规律,进而分析地层结构、划分体系域以及地层层序。

Division of the Cambrian sequences in the Xichuan stratigraphic microprovince, Henan

The Cambrian stratigraphic sequences in the Xichuan stratigraphic microprovince,Henan consist of the Shuikougou,Yuejiaping and Wugongya Formations,which are in parallel unconformable contact with the underlying Sinian strata and in conformable contact or in parallel unconformable contact with the overlying Ordovician strata,characteristic of the type II boundary for both the top and basal boundaries.These stratigraphic sequences are involved in 46 basic sequences,and examined in detail in vertical and horizontal variations,stratal architectures and division of systems tracts.The maximum marine flooding phase occurred during the early Cambrian when the rapid transgressions took place.There are big gaps in lithology of the lower part and upper part of the Cambrian strata,indicating the inhomogeneous uplifting of the crust during the early and latest Cambrian.